2016-12-09T15:24:22ZSilicon drift detectors with integrated JFET: Simulation and designhttp://nopr.niscair.res.in/handle/123456789/30623
Title: Silicon drift detectors with integrated JFET: Simulation and design
Authors: Mehta, Pourus
Abstract: <span style="mso-bidi-language:HI">High resolution, low energy X-ray spectroscopy
systems have been developed recently using the Silicon drift detector (SDD)
with in-built Junction field effect transistor (JFET). A comprehensive
simulation study of the SDD and integrated
<span style="mso-bidi-language:HI">JFET with a view to formulate the design flow has
been carried out. An optimized process flow for fabrication of SDD and
integrated JFET on high resistivity detector substrate is presented. Based on
these studies, several mask layouts for the SDD,
<span style="mso-bidi-language:HI">JFET and reset MOSFET have been designed.
</span></span></span>
Page(s): 705-7132005-09-01T00:00:00ZIterative algorithm for microwave tomography using Levenberg-Marquardt regularization techniquehttp://nopr.niscair.res.in/handle/123456789/30621
Title: Iterative algorithm for microwave tomography using Levenberg-Marquardt regularization technique
Authors: Bandyopadhyay, B; Kundu, A; Datta, A N
Abstract: <span style="mso-bidi-language:HI">An inverse iterative algorithm for microwave
imaging based on moment method solution is presented here. The iterative scheme
has been developed on constrained optimization technique and is certain to
converge. The algorithm is applied to synthetic data and the results of reconstruction
of complex permittivity distribution show a very high degree of accuracy.
Levenberg-Marquardt method solves the ill posedness of the problem.
</span>
Page(s): 649-6532005-09-01T00:00:00ZEffective charges in ternary chalcogenide spinelshttp://nopr.niscair.res.in/handle/123456789/8862
Title: Effective charges in ternary chalcogenide spinels
Authors: Kushwaha, A K; Kushwaha, S S
Abstract: The effective ionic charge <i style="">Z*e</i> of each ion is determined within a narrow variable range for ternary
chalcogenide spinel compounds. The Szigeti effective charge <i style="">e*</i><sub>s</sub> is also evaluated for the
anion and cation using the observed optical dielectric constant Ɛ<sub>ω</sub>. The correlation between <i style="">e*</i><sub>s</sub> and the dielectric
constant Ɛ<sub>ω</sub> are empirically found
as Ɛ<sub>ω</sub>-1=2.0/[(<i style="">e*</i><sub>s</sub>./<i style="">Z</i><sub>eff </sub><i style="">e</i>)+(<i style="">e*</i><sub>s</sub>./<i style="">Z</i><sub>eff </sub><i style="">e</i>)<sup>2</sup>].From effective ionic
charges, we conclude that the ionicity increases in the order oxide >
sulphide > selenide, indium compounds > chromium compounds, normal spinel > inverse spinel.
Page(s): 664-6672005-09-01T00:00:00ZTemperature dependence of lattice energy of fluorite type AB<sub>2</sub> crystals, alkaline earth oxides and heavy metal halides – Evaluation from sound velocity datahttp://nopr.niscair.res.in/handle/123456789/8861
Title: Temperature dependence of lattice energy of fluorite type AB<sub>2</sub> crystals, alkaline earth oxides and heavy metal halides – Evaluation from sound velocity data
Authors: Subrahmanyam, M; Rajagopal, E; Murthy, N Manohara
Abstract: Lattice energies of CaF<sub>2</sub>, SrF<sub>2</sub>,
BaF<sub>2</sub>, CdF<sub>2</sub>, EuF<sub>2</sub>, MgO, SrCl, AgCl and TlBr at
different temperatures have been evaluated making use of single crystal elastic
constant data and employing Kudriavtsev’s theory which relates the lattice
energy of the crystal, <i style="">U</i>, with mean
sound velocity, <i style="">u</i><sub>m</sub>, in the
crystal. The lattice energies of both MgO and SrO decrease with increase in
temperature and the variations are parabolic and similar. The lattice energies
of AgCl and TlBr vary with temperature parabolically up to 80 K and thereafter
linearly up to 300 K. The results are explained in terms of the structure of
the crystals, mutual interaction of the ions and anharmonic effects associated
with as a function of temperature.
Page(s): 660-6632005-09-01T00:00:00Z